Astrofest Rocket "plume" IMAGE

[AstroTourist]

Attached is an image of the rocket "plume" that we observed from Queensland Astrofest on 14 Aug.
I took a series of 8 second images through my 76mm refractor.
14 images stacked in DeepSkyStacker.
On the left is the satellite trailed through movement over the 8 secs of each of the images.
To the right of that is something else which is moving roughly parallel to the satellite but moving away slowly (as seen by the multiple tracks). It varies in brightness over the course of the 14 images (tumbling?). Perhaps it is some component that was discarded as part of the burn (?)
The plume itself is a little smeared over the 8 secs of each image. It is also further smeared because over the course of the 14 images it also moves away from the satellite. When viewed trough the scopes the plume started more from a point and diverged.
So, is it a rocket burn or something else?
Rgds,
Terry

[jjjnettie]

Cheers Terry.
A great capture!
I missed all the excitement, having gone to bed not long after the Astrofeast.

[Liz]

Great capture Terry!!! Wish I could have seen it.
We had some members just SW of Townsville who saw it too, and wondered what the heck it was!!

[renormalised]

Very interesting shot there, Terry. Would be interesting to get a copy of the satellite ephemeris data to determine which bird it was. That looks like a retro firing for a course/attitude correction or orbital insertion burn.

Or, maybe it was unidentified...as in an UFO. They may have been dumping their toilet wastes overboard!!!:):P

[coldspace]

http://www.space.com/missionlaunches/aehf-1-advanced-military-communications-satellite-launch-100814.html

Great capture Terry, I remember seeing it on your laptop on Saturday night in the dinning room.

The 2 objects we are seeing in front of the plume are the last stage of the 51 minute Geo orbit insertion after the 2 nd burn, and also the 13 odd thousand pound military satelite after it was detached from the stage, according to this article.

[h0ughy]

nice capture Terry

[DavidTrap]

Nice capture - how long did this last? (I went home on Saturday morning)

DT

[GrahamL]

15/ 20 minutes maybe?.. nothing streaking across the sky as such
picture an object that appears much like the SMC dosn't look to differant naked eye ( maybe a little brighter and compact) but has just appeared in the sky where it shouldn't be .

great pics Terry , had the cloud disspersed a little when you grabbed those shots ? as it was very well defined visually for quite some time .

[coldspace]

We observed it at Astrofest for say about at least 1 hr probally longer as no one was timing,the event pretty much took over Saturday night observing for the few of us who were using the 20inch SDM, naked eye it was bright for at least 45mins possibly more and appeared like the SMC does, in bino's it started to take on a more plume like shape, and in Jonathans 20inch SDM it clearly was a large tapered exhaust plume in shape with 2 bright dots travelling accross in front.

Terry's picture shows good deal and well done in capture,but in the SDM it was alot sharper/cleaner straight plume/brighter with more contrast because of the real time viewing , and the 2 pieces of the craft were nice bright points moving through the sky. It would have been a hard object to image with the clarity of seeing it live.

It was very apparant that it was a satelite/rocket with exhaust plume in the 20inch. Best thing we have seen for along time.

[DavidTrap]

Ta Gents - my bad for going home!

DT

[astroron]

Hi David great time was had by all, great to catch up with you again.
You may get up to Cambroon before I depart for that Great Observatory in The Sky:P
Astrofest has a habit of throwing up surprises so you should stay to the end,
you never know what will happen next:question:
Cheers:thumbsup:

[gary]

Hi Terry,

Great image! I gather from what I can make out it appears to be tracking close
to sidereal? I understand it was observed from around 9pm to 11pm which
gives credence to it being boosted into a high geostationary orbit. Based on
Matt's link, it will almost certainly be AEHF. Here is a link to some pictures of it
being prepared. http://spaceflightnow.com/atlas/av019/preflight/

Do you happen to know an approx RA/Dec or Az/El for a given time?
Or even what constellation it was in?

[AstroTourist]

Thanks folks for all the comments.



Good work at identifing the object/event. The times match reasonably well.
The timings for the launch (from http://spaceflightnow.com/atlas/av019/ascent.html) were...
Launch at 7:07 EDT (EDT = GMT -4) which puts it at 21:07 EAST
Centaur upper stage engine first burn T+4 mins to T+10 mins or 21:11 to 21:17 EAST
Centaur upper stage engine second burn T+22 mins to T+27 mins or 21:29 to 21:34 EAST
Spacecraft separation T+51 mins = 21:58 EAST.
I took images over the period from 22:44 to 22:54 with the stacked set at 22:46 and that was clearly after payload separation as we see the two travelling independantly and separating.
It would have taken me 10 to 15 mins to attach the camera, focus and set up the imaging run after I first heard the commotion and observed it in my scope. Thanks to those eagle eyed persons that spotted it.
There was quite a bit of coasting after the second burn and before separation, so the cloud could either have been from the second burn or alternatively it may be the the results of the separation process of the satellite from the Centaur upper stage.


Yes, the view in the scopes was much better defined as my image of the cloud is smeared over the 8 secs of each exposure.



Yes, the cloud was dispersing all the time. In my sequence of images it is clearly moving away from the spacecraft and dispersing and at the end of my imaging run it was becoming quite faint. I recall eyeballing it frequently as I was getting the imaging equipment ready and seeing it visibly becoming fainter.... must hurry!!

I have now taken the bold step of identifying the event on the attached image.
Rgds,
Terry

[AstroTourist]

It was moving significantly against the stars. You can see that by the line of each of the stars as the moving image is stacked (each image 10 secs apart). I did not record the location.
I could possibly have a go at identifying the location and speed but no promises...
Rgds,
Terry

[Moon]

Wonderful capture and analysis!
James

[astroron]

I would say that the flair was iether just in Scorpius or in Ophiuchus, as it was just to the right of the head of Scorpius, that was the information I gave out to people to look toward to find it.:astron::thumbsup:

[AstroTourist]

I have located the position of my images in Ophiuchus in the region of Zeta Ophiuchi (not far from the boundary with Scorpius).
Attached is a mosaic of 5 images over the ten minutes of my imaging showing the movement against the background stars. I have added RA & Dec coordinates to define its position. Zeta Ophiuchi is marked. I have added in lines to show the craft's travel between the individual images. It was located at alt 35 deg. Azim 275 deg.
Some comments:
You can see the two components are travelling roughly parallel but drifting apart.
Based on their relative sizes (http://spaceflightnow.com/atlas/av019/diagram.html) I would say that the Centaur is the bright one at the top and the AEHF satellite is the fainter one on the bottom closest to the plume.
The exhause plume is seen drifting away and dispersing over the 10 mins.
The movement is about 6 degrees over the ten minutes so it must not have yet been geo synchronous.
The ground track diagram (http://spaceflightnow.com/atlas/av019/groundtrack.html) puts the vehicle just off the west coast of Western Australia at the time and this sits comfortably with the alt and azimuth of the sighting.
One question:
Is the exhaust plume the lingering result of the second Centaur burn that was completed over an hour earlier or could it be a product of the separation. I think probably from the Centaur burn (and the plume has travelled with the spacecraft).

I will leave it to others to now absolutely confirm that it was AEHF based on the location and time in the image.

Rgds,
Terry

[mozzie]

good stuff terry:thumbsup::thumbsup:
i was hoping that someone imaged

graeme(nightstalker) binos were also great to view the plume

[NickontheCoast]

Thanks for the images. And the further detail - it's widened my horizons and given me more incentive to pan the skies when I can. Guess that's what this game is all about.

[gary]

Hi Terry,

Thanks for the second mosaic. Great work.

A quick back-of-the-envelope calculation and it all adds up.
At UT 12:46 that would correspond to a LAST of 20:36 at Linville.
RA: 16:43 Dec -12 would give an Az of 274 degrees and an Alt of 36 degrees.
That corresponds to an HA of 3:42. So that would put it on the meridian at +96:36E
longitude at that time. So as you mention, indeed it puts it over the Indian Ocean
west of the WA coast and referring to the projected ground track, it looks highly
plausible. Not clear yet whether it is the resultant plume from the earlier burn
obeying the First Law or exhaust from separation.

Once again, well done and a great observation.

[DavidTrap]

Fascinated with this maths (and the images and their RA/Dec overlays too).

I can keep up with this until the fourth line where you mention HA? What is that. How do you then calculate the longitude from that?

High school maths is but a distant memory...

ta in advance,

DT

[gary]

Hi David,

No problem.

HA is the Hour Angle, which is expressed as a time.
So for the object, its HA = LAST - RA
i.e HA = 20:26 - 16:43 = 03:42
(Apologies, in the prior post I made a typo for the LAST, as 20:36 rather than
the correct time of 20:26 - but the result was correct).

We know that there are 24 hours in 360 degrees.
Thus 1 hour = 15 degrees.

Thus 03:42 converted to degrees is 3.71 * 15 = 55.66
The Longitude at Linville is 152.274E.
Thus 152.274 - 55.66 = 96.61E
which is equivalent to 96:36E

Best Regards

Gary

[DavidTrap]

Ok, I think I've got it,

You've identified the RA where the object was visible in the sky, and then calculated the longitude on the planet where that RA would have been on the meridian at that particular time?

I may have my terminology slightly out, but am I on the right track?

Thanks again

DT

[gary]

Hi David,

You have got it!

And your terminology is correct. :thumbsup:

Now armed with an accurately set chronometer (a digital wrist watch will do)
and some star charts with RA marked on them, one could confidently set
sail and know what longitude one is at by noting the time a star crosses the
local meridian.

Best Regards

Gary

[DavidTrap]

Excellent

ta
DT

[AstroTourist]

Hi Gary,
I note your comment ... "back of the envelope"
But I wonder what the inaccuracy in the calculation is due to the object not being on the celestial sphere.
Granted the altitude is high, close to geo synchronous at 23,000 odd km. But there must be some parallax??
Rgds,
Terry

[gary]

Hi Terry,

Indeed there is and it is not necessarily insignificant.

Normally to compute these things we would be transforming geocentric
to/from topocentric and be also taking into account the effects of Earth flattening
and so on.

Even for the Earth's biggest satellite, namely the Moon, as you are aware,
parallax plays a significant part in determining its apparent RA/Dec for a given
topocentric location.

For example, the geosynchronous communications satellites used here in Australia,
like the Optus C1, will have about a 15 minute difference in apparent RA between
a dish pointing here in Sydney and a dish pointing in Perth. These are all
parked up in the equatorial band.

Particularly for any object in a low Earth orbit, like the ISS, topocentric
transformations play a dominant factor in the apparent position.

So with regards the object observed at Duckadang, the one thing we certainly
don't know is its real altitude. All bets are certainly off if it
transpires it was a couple of pranksters with a helium balloon covered in Alfoil
taken from the kitchen and then suspended by string to float above the western
bunkhouse. :lol:

So at the risk of mixing metaphors, the back of the envelope calculation
will get us in the ball park if we assume it was the Atlas/AEHF and that
it was on its way to the high geostationary orbit. If we knew the elevation above
sea level of it at that moment in time from trajectory data, we could get a larger
sheet of paper and refine the calculation some more.

Once again, great image!

[DavidTrap]

I was thinking about parallax error, but assumed that your estimate would have at least been in the ballpark for something heading for geosynchronous orbit.

DT